Railway signaling apparatus



Feb. 14, 1939 D, c. BETTISON RAILWAY S IGNALING APPARATUS Filed Aug. 20, 1955 2 Sheets-Sheet 2 Dashpoz INVENTOR David C.Beztis012 6L2 A ATTQRNEY Patented Feb. 14, 1939 U IT D S ATES PATENT OFFICE 2,147,397 RAILWAY SIGNALING APP ns'rUs David 0. Bettison, Omaha, Application August go, 1935, Serial No. 37,024 20 claims. (01. 24641 My invention relates to railway signaling apparatus ofthe typeinvolving track'circuits, and has for an object the provision; in apparatus of thistype, of atrack circuit having a shunting sensitivitywhich is independent of variations in ballast resistance. More particularly, my invention relates to 'a track relay system Whichis unaffected by a steady value of track current supplied thereto; above a given predetermined minimum value, ort'o gradual changes in this current, but which Will respond positively to a rapid change inthe trackeu'rr'ent received by therelay system, such for example as occurs when a train enters the track circuit.

I willdescribe' three forms of apparatus embodying my invention',andwill then point out the novel features thereof in claims.

The present appli :ation is a continuation in part of my copendi'ng application 'Serial No.

718.490, filed Marcli'31,1934, for Railway signaling'apparatus, insofar as the subject matter common to the two cases is concerned.

In the accompany ng drawingsFig. 1 is a diagrammatic viewshowing one form of apparatus embodying my invention. Fig; 2 is a diagrammatic view showing a modified form of a portion of the apparatus illustrated in Fig. 1. Fig. 3 is a diagrammatic view which shows a further modification of the apparatus illustrated in Fig. l and also embodying my invention.

" Similar reference characters refer to similar partsin each of the views.

Referring to Fig. 1, the reference characters I and l designate the track rails of a stretch of 5 railway track along which traffic normally moves in the direction indicated by the arrow. These rails are divided by insulated joints 2 to form a tracksection D-E. Section DE is provided with a track circuit comprising a battery H and .1 a resistor R connected across the rails at the exit end of the section, as well as the winding of armature A of a relay G connected across the rails at the entering end of the section.

Relay G is a galvanometer type relay comprisl5 ing a field Fjwhich may be either a permanent magnet or an electromagnet, and a movable armature A which carries the track WindingW and which is arranged to rotate about a shaft P, in the field set up by the pole pieces of the magnet 50 F. A cylindrical soft iron core C may be used to provide uniform flux distribution in the armature air gap, in well known manner. One terminal of the armature winding W is connected with rail l by means of wire 3, and the other terminal is connected with rail l by means of wire 4. A tension spring S provides the restraining force against whicli'the armature torque is developed whencurrent flows in winding W. The terminals of winding Ware so connected with the respective track railsthatcurrent from battery H will 9;'t l'le purpose of whichwill be explained herein- A bel ow."

Contact 85 controls the energizing circuit for a relay T'which'lfn ay'be used to-control, over its contacts l 3-'" H l and IL-l9, any suitable apparatus c'onnnonly controlled by'the usual track relay, such for example as lamps G and R of the signal L, which e'e er gized from a source of current having" the terminals BC over the wires 20"a'nd 2 i e spectively1' The circuit for relay T may betracedfrcmpne terminal of the battery l3,wir' e jlLcontact 8 5, wirell, winding of relay"T,"a nd wirelgfto the other terminal of the Thejspring member 6 is sugfliciently flexible to permitrnembersi and} to separate readily upon the occurrence of a quick'clockwise movement of armature A, the static inertia of vane 9 acting to prevent instantaneous follow of segment 1 and member '6. 'Ifgfa'ter damping is desired, over that resulting from the inertia of vane 9 and bear- Ato rotate in the countering an d gear tooth fricti'omthe vane 9 can be made of 'non-Inagnetizable conducting material such as aluminum or copper, and made to rotate in the field of astrong permanent magnet such as M; whereby increaseddamping will be available'due'to the 'eddy' current effect in the vane. The contactspring 8 is designed to have an appreciable amount of'co mpressioncr follow, so that the rigi'd contacifimember 5 may move through an appreciable arc (when the current in winding W decreases"sudde nly) before contact 8-5 opens. The stop pin l 5limits the maximum counterclockwisemovel'nentofsegment'l; and the stop pin I6 acts to opencontact' 8- 5, 'shculd the track current fall 'belowa 'value'which is established as a ness of the train shunt.

minimum at which the track circuit can be safely operated in wet weather.

In describing the operation of the apparatus as a whole, I shall assume that with the apparatus in the normal condition as illustrated, a train enters section D-E. The shunt afforded by the wheels and axles of the train will suddenly reduce the amount of current flowing in winding W, whereupon armature A and contact member 5 will quickly rotate in the clockwise direction due to the restoring force of the spring S. The amount of rotation will depend upon the effective- Due to the inertia of vane 9, spring member 6 will not follow the quick movement of member 5, so that contact 8-5 will open, releasing relay T, thus closing back contact i5l 9 which causes lamp R of signal L to become energized. As soon as armature it of relay T drops, the brake pad M will engage the periphery of vane 9, to prevent further movement of the vane as well as of member 5, until such time as the train leaves the section and contact 85 becomes closed to reenergize relay T.

When the train leaves section D-E, there will be an increase in the current through winding W, and this change will cause armature A and memher 5 to rotate in the counter-clockwise direction, closing contact 8--5, and restoring the apparatus to its normal condition.

It will be apparent from the foregoing that the opening of contact 8-5 of relay G, and therefore the release of relay T, is independent of the track energy level and is dependent only on a quick change in the amount of current supplied to Winding W, this change being of a relatively small value and constant for any energy level. Therefore, changes in the characteristics of the track circuit due to variations in ballast resistance, track battery voltage, or other conditions, will not alfect the operation of the system. To make the operation more clear, let it be assumed, for example, that winding W has a resistance of 4 ohms and is receiving a current of 150 milliamperes with the track unoccupied and ballast dry. The follow or compression of spring 3 may be so adjusted that a change of 30 milliamperes is required to open contact 85. If the current in winding W drops to milliamperes when a train enters the section, then contact 8-5 will open when this current has decreased to milliamperes, and relay T will release to keep segment 7 and member 6 fixed in position thereafter. When the train leaves the section, contact 8-5 will re-close as soon as the current has increased to 120 milliamperes, picking up relay T and disengaging the brake from the vane, so that any further increase in current results in compression of contact 8-5, and movement of segment 1 to the left.

As explained in the above example, any shunt which is sufficient to reduce the current in winding W by 30 milliamperes will cause a release of relay T, irrespective of the initial track energy level. On the other hand, a track circuit of the usual type, employing a 4 ohm track relay energized with milliamperes of current during dry weather requires a train shunt of sufliciently low resistance to reduce the relay current from 150 to approximately 40 milliamperes, depending on the relay design. That is, the train shunt must be low enough to by-pass 110 milliamperes, instead of 30 as in the illustration given above. The increased shunting sensitivity of the apparatus embodying my invention is therefore self-evident.

Since ordinary changes in ballast resistance and track battery voltage occur slowly, contact 85 will remain closed during any movement of armature A resulting. from such changes.

Referring now to Fig. 2, I have shown one manner in which the apparatus embodying my invention may be applied to an alternating current track circuit. The rails of section D E are supplied with alternating current from a source BX--CX, through a track transformer TR and a current-limiting reactor X. At the relay end of the track circuit, a rectifier K is interposed between the rails and the track winding W of relay G, for the purpose of converting the alternating rail current into unidirectional current for operating the relay G. The operation of the system from this point on is the same as previously described, and will be clear without further explanation.

It is to be noted that the design of the relay G may be varied in numerous ways, while at the same time accomplishing the essential purposes of my invention. For example, it is not essential that the soft iron core C be used. Furthermore, the coil W may be wound on a movable soft iron armature, for increasing the armature torque. Also, other means than the spring. S may be used for biasing the armature A to the deenergized position. Similarly, it is contemplated that quick movement of member 6 may be retarded in numerous other suitable ways, as for example by a dashpot arrangement operated by member 6, and locked against subsequent movement by the release of armature l3 of relay T.

Although relay T has been shown as a slow pickup relay, it will be understood that the slow pickup feature, while helpful, is not essential for the proper operation of the system. Also, if desired, the flexible member 6 may be provided with an insulated hook which engages the rigid member 5 to prevent further clockwise movement of armature A, thus establishing a maximum permissible opening for contact 85 to make it unnecessary for member 5 to move through more than a small are before contact 8-5 is closed, upon the exit of a train from the section.

Furthermore, the geared vane 9 may be dispensed with by attaching a magnetic drag vane, or other inertia apparatus, directly to the. free end of flexible member 6.

Referring to Fig. 3, the apparatus of this figure accomplishes substantially the same results as the apparatus of Fig. l, but makes use of a tractive type relay TR in place of the galvanometer relay G. Track relay TR is so designed that armature A will occupy a position corresponding to the amount of energy received by winding W from the track. For example, when the track ballast is dry, the armature A will be in its high position close to the pole face of magnet L, whereas when the track ballast is wet, armature A will be in its low position. For ballast conditions in betweenthese two extremes, armature A will occupy an intermediate position. The particular air gap design for accomplishing this result may vary considerably. For example, armature A may be of the plunger type or of the Z-armature type, or of any other suitable design. The restraining force for armature A may be provided by a suitable weight or by a spring such as the spring S shown in the drawings.

Armature A carries a contact finger 22 which cooperates with a contact disc 23 attached to shaft 3! of a dashpot P. If the movement of armature A is slow, such as that resulting from a change in ballast conditions, disc 23 Will follow the movement of finger 22 and the contact 2223 will remain closed. If, however, a train enters the section, armature A will drop quickly and contact 22-23 will open, thus deenergizing the brake relay BR. and also the signal control relay T. The circuit for relays BR and T includes battery B, wires 26 and 21, contact 23-22, and wires 28 and 29. When the armature of relay BR drops, finger 36 causes the brake 24, which is pivoted at 25, to press against the shaft 33 of the dashpot, thus preventing a change in the position of disc 23 until relay TR picks up following the exit of the train from the section.

It will be apparent from the foregoing description that the apparatus of Fig. 3 provides the same type of operation as provided by the apparatus of Fig. l, and it is believed that the complete operation of this apparatus will be clear without further explanation from a comparison with Fig. 1.

It is not essential, of course, that a dashpot be used, as any movable member so designed that it can be moved slowly without undue resistance but in which a rapid movement is restrained, can be used to cooperate with the disc 23 and finger Although I have herein shown and described only three forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope or" the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

i. In combination, a section of railway track, a source of current connected across the rails or" saic section, a control relay, a circuit including a normally closed contact for energizing said relay, means receiving energy from said rails for corn trolling said contact in such manner that said contact will open upon a sudden decrease in the energy received by said means but that contact will remain closed when the energy change occurs slowly, means governed by sai relay effective when said contact opens and said relay becomes deenergized for preventing the contact from reclosing until a predetermined increase in the energy received by said ocours, and signaling apparatus governed by said control relay.

2. In combination, a section of railway track, a source of current connected across the rails of said section, a first relay receiving energy from said rails having a movable armature which as sumes different positions in accordance with the amount of energy received by said relay, a com tact operated by said armature and comprising a rigid member and a flexible member normally in contact with each other, inertia means operated by said flexible member for causing said contact to open upon a quick movement of said armature but to remain closed when the move ment of said armature is gradual, a second relay controlled by said contact, means controlled by said second relay for at times preventing operation of said flexible member by said armature, and signaling apparatus governed by said second relay.

3. In combination, a section of railway track, a source of current connected across the rails of said section, a galvanometer relay receiving energy from said rails and having a movable member which assumes different positions in accordance with the amount of energy received by said relay, a contact having inertia means associated therewith and operated by said movable member in such manner that said contact will remain closed when the movement of said member is gradual but will open upon a sudden movement of said member resulting from the entry of a train into said section, and signaling apparatus controlled by said contact.

4. In combination, a section of railway track, a source of current for said section, means receiving energy from said rails and movable to different positions determined in accordance with the amount of energy received from said rails, a normally closed contact operated by said means and comprising a rigid and a flexible member which move as a unit when the movement of said means is gradual, a damping vane operated by the flexible member of said contact for causing said contact to open upon a quick movement of said means, and signaling apparatus controlled by said contact.

5. In combination, a section of railway track, a source of current connected across the rails of said section, a control relay, a circuit including a normally closed contact for energizing said relay, means receiving energy from said rails for controlling said contact in such manner that said contact will open upon a sudden decrease in the energy received by said means but that said contact will remain. closed when the energy change occurs slowly, and means governed by said relay for preventing said contact from reclosing until the energy received by said means reaches a level determined by the energy level existing at the time said contact initially opens.

63. In combination with a section of railway track provided with a track circuit including a source of energy, a winding receiving energy from said track circuit, a first contact member biased to one position and urged against such bias by the force of said winding, a second contact member normally occupying a given relation with respect to said first contact member, and means including a dashpot effective during a rapid but not during a gradual change in the force applied to said first member for changing the relation of said two contact members.

7. In combination with a section of railway track provided with a track circuit including a source of energy, a track relay receiving energy from said track circuit and having an armature which adjusts its position in accordance with the amount of energy received by the relay, a first contact member biased to one position and urged by the force of said armature against said bias, a second contact member normally occupying a given relation with respect to said first contact member, and means effective during a rapid but not during a gradual change in the position of said armature for changing the relation of said two contact members.

8. In combination with a section of railway track provided with a track circuit including a source of energy, a track relay receiving energy from said track circuit and having a core and an armature separated by an air gap the length of which varies in accordance with the amount of energy received by said relay, a first contact member biased to one position and urged by the force of said armature against said bias, 2. second contact member normally occupying a given relation with respect to said first contact member, and means effective during a rapid but not during a gradual change in the length of said air gap for changing the relation of said two contact members.

9. In combination with a section of railway ill track provided with a track circuit including a source of energy, a winding receiving energy from said track circuit, a first contact member biased to oneposition and urged against such bias by the force of said winding, a second contact member normally occupying a give-n relation with respect to said first contact member, means effective during a rapid but not during a gradual decrease in the force applied to said first member for changing the relation of said two contact members, and means controlled by said two contact members effective when said given relation between them is changed for fixing the position of said second contact member.

10. In combination with a section of railway track provided with a track circuit including a source of energy, a winding receiving energy from said track circuit, a first contact member biased to one position and urged against such bias by the force of said winding, a second contact member normally engaging said first contact member, means effective during a rapid but not during a gradual decrease in the force applied to said first member for separating said two contact members, and means controlled by said two contact members efiective upon the separation thereof for fixing the position of said second contact member until such time as said first contact member engages said second contact member.

11. In combination with a section of railway track provided with a track circuit including a source of energy, a winding receiving energy from said track circuit, a first contact member biased to one position and urged against such bias by the force of said winding, a second contact member normally occupying a given relation with respect to said first contact member, and a retarding mechanism operatively connected with said second contact member, whereby the relation between said two contact members will be changed during a rapid but not during a gradual change in the force applied to said first contact member.

12. A galvanometer relay for railway signaling track circuits comprising, in combination, a movable coil adapted to be energized from the track and occupying progressively different positions in accordance with the amount of energy received from the track, a normally closed contact operated by said movable coil, and means for causing said contact to open upon a relatively quick change in said energy but to remain closed when the change in energy received by said movable coil is gradual, whereby said relay is capable of distinguishing between the presence of a train shunt and changes in ballast resistance of said track.

13. A galvanometer relay for railway signaling track circuits comprising, in combination, a movable coil adapted to be energized from the track and occupying progressively different positions in accordance With the amount of energy received from the track, a first contact member biased to one position and urged against such bias by the force applied thereto by said movable coil, a second contact member normally engaging said first contact member, and means effective during a rapid but not during a gradual change in the force applied to said first member for separating said two contact members.

14. A relay for railway signaling track circuits comprising, in combination, a movable element adapted to be energized from the track and occupying different positions in accordance with the amount of energy received from the track, a first contact member biased to one position and urged against such bias by the force applied thereto by said movable element, a second contact member normally occupying a given relation With respect to said first contact member, means efiective during a rapid but not during a gradual change in the force applied to said first member for changing the relation of said two contact members, and means controlled by said two contact members efiective when said given relation between them is changed for fixing the position of one of said contact members.

15. In combination with .a section of railway track and a source of current connected across the rails of said section, a track relay energized from the rails of said section, an armature for said track relay comprising a movable element which occupies progressively different positions in accordance with the amount of energy received from the track by said track relay, and means eifective during a rapid change in the energy received by said track relay such as occurs when a train enters the section but not during a grad ual change resulting from a variation in ballast resistance for preventing movement of said movable element until the train vacates said section.

16. In combination with a section of railway track and a source of current connected across the rails of said section, a track relay energized from the rails of said section over a circuit of substantially constant resistance between the rails and said track relay, means for causing the armature of said relay to respond differently to a sudden change such as occurs when a train enters the section and a gradual change such as occurs due to ballast resistance Variation, and means effective upon said sudden change for fixing the pickup point of said armature in accordance with the track relay energization existing just prior to said sudden change.

17. In combination with a section of railway track and a source of current connected across the rails of said section, a track relay energized from the rails of said section over a circuit of substantially constant resistance between the rails and said track relay, a contact for said track relay, means eifective upon a sudden change but not upon a gradual change in the energy received by said track relay for operating said contact, and means effective following said sudden change for maintaining said contact in its operated condition by constraining the mechanical movement thereof.

18. In combination with a section of railway track and a source of current connected across the rails of said section, a galvanometer track relay energized from the rails of said section over a circuit of substantially constant resistance between the rails and said track relay, a movable coil for said track relay occupying progressively diiferent positions in accordance with the amount of energy received from the rails by said track relay, a normally closed contact operated by said movable coil, and means effective upon a sudden change in said energy for causing opening of said contact.

19. In combination, a section of railway track, a source of current connected across the rails of said section, a control relay, an energizing circuit for said control relay, a normally closed contact included in said circuit, retarding means associated with said contact, a winding receiving energy from said rails for controlling said contact in cooperation with said retarding means in such manner that said contact will open when and only when a sudden predetermined decrease in the energy received by said winding occurs but that said contact will remain closed when the energy change occurs slowly, and signaling apparatus governed by said control relay.

20. In combination, a section of railway track, a source of current connected across the rails of said section, an auxiliary relay receiving energy from said rails and having a normally closed contact which opens on a predetermined small decrease in the energy received by said auxiliary relay when a train enters said section, a control relay, an energizing circuit for said control relay governed by said contact, means governed by said control relay for determining the amount of energy at which said auxiliary relay willreclose said contact upon the exit of the train in accordance with the magnitude of the ballast resistance of said track section, and signaling apparatus governed by said control relay.

DAVID C. BETTISON. 

